TECHNICAL FIELD
[0001] The present invention relates to a vehicle.
BACKGROUND ART
[0002] Patent Documents 1, 2, and 3 disclose a vehicle equipped with a fuel cell. In a vehicle
equipped with a fuel cell, a liquid such as fuel cell drainage, a coolant, or oil
flows.
[0003] The vehicle is also equipped with a housing that accommodates a power transmission
mechanism. Patent Documents 4 and 5 disclose that a housing is provided with a covering
as a soundproof member.
PRIOR ART DOCUMENT
PATENT DOCUMENT
SUMMARY OF INVENTION
PROBLEM TO BE SOLVED BY THE INVENTION
[0005] A vehicle is required to effectively use a liquid.
SOLUTIONS TO THE PROBLEM
[0006] A vehicle according to an aspect of the present invention is a vehicle including:
a housing configured to accommodate a power transmission mechanism;
a covering having a portion that covers the housing; and
a liquid interposed between an outer surface of the covering and an outer surface
of the housing.
[0007] A vehicle according to an aspect of the present invention includes:
a housing configured to accommodate a power transmission mechanism; and
a heat exchange unit configured to perform heat exchange between the housing and a
liquid that is fuel cell drainage.
ADVANTAGEOUS EFFECTS OF THE INVENTION
[0008] According to an aspect of the present invention, the liquid can be effectively used.
BRIEF DESCRIPTION OF DRAWINGS
[0009]
[FIG. 1] FIG. 1 is a skeleton diagram illustrating a unit mounted on a vehicle.
[FIG. 2] FIG. 2 is an external view of the unit.
[FIG. 3] FIG. 3 is a schematic cross-sectional view of the unit.
[FIG. 4] FIG. 4 is an enlarged diagram around a planetary reduction gear.
[FIG. 5] FIG. 5 is a top view of a motor case with a second case member removed.
[FIG. 6] FIG. 6 is a diagram illustrating a circulation system of cooling water in
the unit.
[FIG. 7] FIG. 7 is a view illustrating a catch tank of a gear case.
[FIG. 8] FIG. 8 illustrates a covering that covers a housing and a box that introduces
a liquid.
[FIG. 9] FIG. 9 is a diagram of FIG. 8 when viewed from a rotation axis direction.
[FIG. 10] FIG. 10 is a view illustrating a vehicle equipped with the unit and a fuel
cell.
[FIG. 11] FIG. 11 is a view illustrating a state in which the box is viewed from above
together with the housing.
[FIG. 12] FIG. 12 is a view illustrating a cross section of the box taken along line
A-A in FIG. 11 together with the housing.
[FIG. 13] FIG. 13 is a schematic diagram illustrating a covering according to Modification
1.
[FIG. 14] FIG. 14 is a schematic diagram of the covering according to Modification
1 when viewed from a rotation axis X direction.
[FIG. 15] FIG. 15 is a diagram illustrating a covering according to Modification 2.
DESCRIPTION OF EMBODIMENTS
[0010] First, definitions of terms in the present description will be described.
[0011] A "unit" is also referred to as a "motor unit", a "power transmission device", or
the like. The motor unit is a unit that includes at least a motor. The power transmission
device is a device that includes at least a power transmission mechanism, and is,
for example, a gear mechanism and/or a differential gear mechanism. A unit that is
a device including a motor and a power transmission mechanism belongs to concepts
of both the motor unit and the power transmission device.
[0012] A "housing" accommodates a motor, a gear, and an inverter. The housing includes one
or more cases.
[0013] "3-in-1" means a form in which a part of a motor case accommodating a motor and a
part of an inverter case accommodating an inverter are integrally formed. For example,
when a cover and a case constitute one case, in "3-in-1", the case accommodating a
motor and the case accommodating an inverter are integrally formed.
[0014] A "motor" is a rotating electrical machine that has a motor function and/or a generator
function.
[0015] When referring to a second element (component, portion, or the like) connected to
a first element (component, portion, or the like), the second element (component,
portion, or the like) connected downstream of the first element (component, portion,
or the like), and the second element (component, portion, or the like) connected upstream
of the first element (component, portion, or the like), it means that the first element
and the second element are connected such that power can be transmitted. A power input
side is upstream, and a power output side is downstream. The first element and the
second element may be connected to each other via another element (clutch, other gear
mechanism, or the like).
[0016] The description "overlap when viewed in a predetermined direction" means that a plurality
of elements are disposed in a predetermined direction, and has the same meaning as
the description "overlap in a predetermined direction". The "predetermined direction"
is, for example, an axial direction, a radial direction, a gravity direction, or a
vehicle traveling direction (vehicle forward direction, vehicle backward direction).
[0017] When the drawing illustrates that a plurality of elements (components, portions,
or the like) are disposed in a predetermined direction, in the description of the
present description, it may be considered that there is a sentence explaining that
the plurality of elements overlap when viewed in the predetermined direction.
[0018] The descriptions "do not overlap when viewed in a predetermined direction" and "offset
when viewed in a predetermined direction" mean that a plurality of elements are not
disposed in a predetermined direction, and have the same meaning as the descriptions
"do not overlap in a predetermined direction" and "offset in a predetermined direction".
The "predetermined direction" is, for example, an axial direction, a radial direction,
a gravity direction, or a vehicle traveling direction (vehicle forward direction,
vehicle backward direction).
[0019] When the drawing illustrates that a plurality of elements (components, portions,
or the like) are not disposed in a predetermined direction, in the description of
the present description, it may be considered that there is a sentence explaining
that the plurality of elements do not overlap when viewed in the predetermined direction.
[0020] The description "a first element (component, portion, or the like) is positioned
between a second element (component, portion, or the like) and a third element (component,
portion, or the like) when viewed in a predetermined direction" means that when viewed
from the predetermined direction, it can be observed that the first element is between
the second element and the third element. The "predetermined direction" is an axial
direction, a radial direction, a gravity direction, a vehicle traveling direction
(vehicle forward direction, vehicle backward direction), or the like.
[0021] For example, when the second element, the first element, and the third element are
disposed in this order along the axial direction, it can be said that the first element
is positioned between the second element and the third element when viewed in the
radial direction. When the drawing illustrates that the first element is positioned
between the second element and the third element when viewed in a predetermined direction,
in the description of the present description, it may be considered that there is
a sentence explaining that the first element is between the second element and the
third element when viewed in the predetermined direction.
[0022] In a case in which two elements (components, portions, or the like) overlap when
viewed in the axial direction, the two elements are coaxial.
[0023] The "axial direction" means an axial direction of a rotation axis of a component
that constitutes a unit. The "radial direction" means a direction orthogonal to the
rotation axis of the component that constitutes the unit. The component is, for example,
a motor, a gear mechanism, or a differential gear mechanism.
[0024] When a rotating element (for example, sun gear, carrier, or ring gear) of a planetary
gear mechanism is "fixed" to another element, the rotating element may be directly
fixed or may be fixed via another member.
[0025] A "downstream side in a rotation direction" means a downstream side in a rotation
direction when a vehicle moves forward or in a rotation direction when the vehicle
moves backward. It is preferable to regard it as the downstream side in the rotation
direction when the vehicle moves forward, which occurs frequently. A downstream side
in a rotation direction of the planetary gear mechanism means a downstream side in
a revolution direction of a pinion gear.
[0026] A "catch tank" is an element (component, portion, or the like) that has a function
of a tank (container) into which oil is introduced. Supplying the oil from an outside
of the tank to the tank is expressed as "catch". The catch tank is provided, for example,
using at least a part of the housing, or is provided separately from the housing.
Integrally forming the catch tank and the housing contributes to a reduction in the
number of components.
[0027] A "coolant" is a refrigerant and is a type of heat exchange medium. For example,
the "coolant" is a liquid (cooling water or the like) or a gas (air or the like).
The coolant is a concept that includes oil, but when both the oil and the coolant
are described in the present description, it means that the coolant is made of a material
different from that of the oil.
[0028] A "heat exchange unit" is an element (component, portion, or the like) that exchanges
heat between two different heat exchange media. Combinations of the two heat exchange
media are, for example, oil and cooling water, cooling water and air, or air and oil.
The heat exchange unit includes, for example, a heat exchanger (oil cooler), a flow
path through which a coolant flows, and a heat pipe. In the present invention, it
is preferable to use a covering that covers the housing as the heat exchange unit.
[0029] The covering is a component separate from the housing. For example, a liquid serving
as the coolant is introduced between an outer surface of the covering and an outer
surface of the housing. Heat exchange between the coolant and the oil and/or air in
the housing is performed via a wall portion of the housing.
[0030] A "vehicle room" means a room in a vehicle into which passengers enter.
[0031] Hereinafter, an embodiment of the present invention will be described.
[0032] FIG. 1 is a skeleton diagram illustrating a unit mounted on a vehicle.
[0033] FIG. 2 is an external view of the unit.
[0034] FIG. 3 is a schematic cross-sectional view of the unit. FIG. 3 illustrates a state
in which an inverter case is removed.
[0035] FIG. 4 is an enlarged diagram around a planetary reduction gear.
[0036] FIG. 5 is a top view of a motor case with a second case member removed.
[0037] FIG. 6 is a diagram illustrating a circulation system of cooling water in the unit.
[0038] FIG. 7 is a diagram illustrating a catch tank of a gear case.
[0039] As illustrated in FIG. 1, a unit 1 is a 3-in-1 unit, and includes a motor 2, a power
transmission mechanism 3 that transmits power output from the motor 2 to drive wheels
K and K of the vehicle, and an inverter 7 (see FIG. 2) that is a power conversion
device of the motor 2.
[0040] In the embodiment, as illustrated in FIG. 1, the unit 1 includes, which are the power
transmission mechanism 3, a planetary reduction gear 4 (reduction gear mechanism,
planetary gear mechanism), a differential mechanism 5 (differential gear mechanism),
and drive shafts DA and DB as output shafts.
[0041] In the unit 1, the planetary reduction gear 4, the differential mechanism 5, and
the drive shafts DA and DB are provided along a transmission path of output rotation
around a rotation axis X of the motor 2. Axes of the drive shafts DA and DB are coaxial
with the rotation axis X of the motor 2, and the differential mechanism 5 is coaxial
with the motor 2.
[0042] In the unit 1, the output rotation of the motor 2 is decelerated by the planetary
reduction gear 4 and input to the differential mechanism 5, and then transmitted to
the left and right drive wheels K and K of the vehicle equipped with the unit 1 via
the drive shafts DA and DB.
[0043] Here, the planetary reduction gear 4 is connected downstream of the motor 2. The
differential mechanism 5 is connected downstream of the motor 2 via the planetary
reduction gear 4. The drive shafts DA and DB are connected downstream of the differential
mechanism 5.
[0044] As illustrated in FIG. 2, the unit 1 includes, as a 3-in-1 type housing, a housing
HS that accommodates the motor 2, the power transmission mechanism 3 and the inverter
7. The housing HS includes one or more cases. The housing HS includes, for example,
a motor case 10 that accommodates the motor 2, a gear case 14 that accommodates the
power transmission mechanism 3, and an inverter case 17 that accommodates the inverter
7. The gear case 14 is joined to one end of the motor case 10 in a rotation axis X
direction. The inverter case 17 is joined above the motor case 10 in a gravity direction
when the unit 1 is mounted on the vehicle.
[0045] The inverter 7 is an electronic component including a smoothing capacitor, a power
semi-conductor element, a driver board, and the like. The inverter 7 is electrically
connected to the motor 2 inside the motor case 10 by wiring (not illustrated).
[0046] In the inverter case 17, a cooling path CP2 through which cooling water CL (see FIG.
6) for cooling the inverter 7 flows is formed.
[0047] The motor 2 has a portion that overlaps the differential mechanism 5 (differential
gear mechanism) when viewed in an axial direction (see FIG. 3). Here, "when viewed
in an axial direction" means when viewed from the rotation axis X direction. "When
viewed in a radial direction" means when viewed from the radial direction of the rotation
axis X direction.
[0048] When viewed in the axial direction, the motor 2 has a portion that overlaps the planetary
reduction gear 4 (reduction gear mechanism).
[0049] When viewed in the axial direction, the planetary reduction gear 4 (reduction gear
mechanism) has a portion that overlaps the differential mechanism 5 (differential
gear mechanism).
[0050] When viewed in the axial direction, the planetary reduction gear 4 (reduction gear
mechanism) has a portion that overlaps the motor 2.
[0051] When viewed in the axial direction, the differential mechanism 5 (differential gear
mechanism) has a portion that overlaps the planetary reduction gear 4 (reduction gear
mechanism).
[0052] When viewed in the axial direction, the differential mechanism 5 (differential gear
mechanism) has a portion that overlaps the motor 2.
[0053] When viewed in the axial direction, the motor 2 has a portion that overlaps the differential
mechanism 5 (differential gear mechanism).
[0054] As illustrated in FIG. 3, the motor case 10 includes a first case member 11, a second
case member 12 fitted onto the first case member 11, and a cover member 13 joined
to one end of the first case member 11. The first case member 11 includes a cylindrical
support wall portion 111 and a flange-shaped joint portion 112 provided at one end
111a of the support wall portion 111.
[0055] The support wall portion 111 is provided in a direction along the rotation axis X
of the motor 2. The motor 2 is accommodated inside the support wall portion 111.
[0056] The second case member 12 includes a cylindrical peripheral wall portion 121, a flange-shaped
joint portion 122 provided at one end 121a of the peripheral wall portion 121, and
a flange-shaped joint portion 123 provided at the other end 121b of the peripheral
wall portion 121.
[0057] The peripheral wall portion 121 of the second case member 12 is formed with an inner
diameter that allows the peripheral wall portion 121 to be fitted onto the support
wall portion 111 of the first case member 11.
[0058] The first case member 11 and the second case member 12 are assembled to each other
by fitting the peripheral wall portion 121 of the second case member 12 onto the support
wall portion 111 of the first case member 11.
[0059] The joint portion 122 at the one end 121a of the peripheral wall portion 121 comes
into contact with the joint portion 112 of the first case member 11 from the rotation
axis X direction. These joint portions 122 and 112 are connected to each other with
bolts (not illustrated).
[0060] As illustrated in FIG. 5, a protrusion 111b is provided on an outer periphery of
the support wall portion 111 of the first case member 11. The protrusion 111b is a
wall surrounding the rotation axis X at intervals. The protrusion 111b of the support
wall portion 111 is provided in a spiral shape with a phase shifted from one end toward
the other end in the rotation axis X direction. The protrusion 111b surrounds the
outer periphery of the support wall portion 111 over entire circumference of the support
wall portion 111.
[0061] As illustrated in FIG. 3, the peripheral wall portion 121 of the second case member
12 is fitted onto the support wall portion 111 of the first case member 11. In this
state, since an inner periphery of the peripheral wall portion 121 comes into contact
with an outer periphery of the spiral protrusion 111b of the support wall portion
111, a space is formed between the peripheral wall portion 121 and the support wall
portion 111. The space surrounds the rotation axis X with a gap therebetween and is
continuously formed in a spiral shape in the rotation axis X direction. The spiral
space forms a cooling path CP1 through which the cooling water CL (see FIG. 6), which
is a coolant, flows. In FIG. 6, the spiral cooling path CP1 is simplified and illustrated
as a straight line.
[0062] On the outer periphery of the support wall portion 111 of the first case member 11,
ring grooves 111c and 111c are formed on both sides of a region in which the protrusion
111b is provided. Seal rings 113 and 113 are fitted and attached to the ring grooves
111c and 111c.
[0063] The seal rings 113 are pressed against the inner periphery of the peripheral wall
portion 121 fitted onto the support wall portion 111 to seal gaps between the outer
periphery of the support wall portion 111 and the inner periphery of the peripheral
wall portion 121.
[0064] A wall portion 120 (cover) extending radially inward is provided at the other end
121b of the second case member 12. The wall portion 120 is provided in a direction
orthogonal to the rotation axis X. An opening 120a through which the drive shaft DA
is inserted is provided in a region of the wall portion 120 that intersects with the
rotation axis X.
[0065] A tubular motor support portion 125 that surrounds the opening 120a and extends toward
the motor 2 is provided on a surface of the wall portion 120 closer to the motor 2
(right side in the drawing).
[0066] The motor support portion 125 is inserted inside a coil end 253b, which will be described
later. The motor support portion 125 faces an end portion 21b of a rotor core 21 with
a gap therebetween in the rotation axis X direction. A bearing B1 is supported on
an inner periphery of the motor support portion 125. An outer periphery of a motor
shaft 20 is supported by the motor support portion 125 via the bearing B1.
[0067] A tubular wall portion 126 extending toward the differential mechanism 5 is provided
on a surface of the wall portion 120 closer to the differential mechanism 5 (left
side in the drawing). The tubular wall portion 126 has a cylindrical shape surrounding
the opening 120a, and an inner periphery of the tubular wall portion 126 supports
a bearing B2. The bearing B2 supports a tubular wall portion 61 of a differential
case 50, which will be described later.
[0068] The cover member 13 includes a wall portion 130 orthogonal to the rotation axis X
and a joint portion 132.
[0069] When viewed from the first case member 11, the cover member 13 is positioned on an
opposite side (right side in the drawing) to the differential mechanism 5. The joint
portion 132 of the cover member 13 is joined to the joint portion 112 of the first
case member 11 from the rotation axis X direction. The cover member 13 and the first
case member 11 are connected to each other with bolts (not illustrated). In this state,
in the first case member 11, an opening of the support wall portion 111 closer to
the joint portion 122 (right side in the drawing) is closed by the cover member 13.
[0070] In the cover member 13, an insertion hole 130a for the drive shaft DA is provided
in a central portion of the wall portion 130.
[0071] A lip seal RS is provided on an inner periphery of the insertion hole 130a. The lip
seal RS brings a lip portion (not illustrated) into elastic contact with an outer
periphery of the drive shaft DA. A gap between the inner periphery of the insertion
hole 130a and the outer periphery of the drive shaft DA is sealed by the lip seal
RS.
[0072] A peripheral wall portion 131 surrounding the insertion hole 130a is provided on
a surface of the wall portion 130 closer to the first case member 11 (left side in
the drawing). The drive shaft DA is supported on an inner periphery of the peripheral
wall portion 131 via a bearing B4.
[0073] A motor support portion 135 and a connection wall 136 are provided on an inner diameter
side of the joint portion 132. The motor support portion 135 is provided closer to
the motor 2 (left side in the drawing) when viewed from the peripheral wall portion
131. The motor support portion 135 has a tubular shape surrounding the rotation axis
X with a gap therebetween.
[0074] The cylindrical connection wall 136 is connected to an outer periphery of the motor
support portion 135. The connection wall 136 is formed with a larger outer diameter
than the peripheral wall portion 131 in the wall portion 130 (right side in the drawing).
The connection wall 136 is provided along the rotation axis X and extends away from
the motor 2. The connection wall 136 connects the motor support portion 135 and the
joint portion 132.
[0075] One end 20a of the motor shaft 20 penetrates an inner side of the motor support portion
135 from the motor 2 side to the peripheral wall portion 131 side.
[0076] A bearing B1 is supported on an inner periphery of the motor support portion 135.
The outer periphery of the motor shaft 20 is supported by the motor support portion
135 via the bearing B1.
[0077] A lip seal RS is provided at a position adjacent to the bearing B 1.
[0078] Oil holes 136a and 136b are provided in an inner periphery of the connection wall
136. Oil OL flows from the oil hole 136a into a space (internal space Sc) surrounded
by the connection wall 136. The oil OL flowing into the internal space Sc is discharged
from the oil hole 136b. The lip seal RS is provided to prevent the oil OL in the connection
wall 136 from flowing into the motor 2.
[0079] The gear case 14 includes a peripheral wall portion 141 and a flange-shaped joint
portion 142 provided at an end portion of the peripheral wall portion 141 closer to
the motor case 10. A support portion 145 for a bearing B2, which will be described
later, is provided at an end portion of the peripheral wall portion 141 on a side
(left side in the drawing) opposite to the joint portion 142. The peripheral wall
portion 141 includes a tubular wall portion 141a connected to the joint portion 142,
an inclined portion 141c (inclined surface) connected to the support portion 145,
and a connection wall portion 141b connecting the tubular wall portion 141a and the
inclined portion 141c. The tubular wall portion 141a and the connection wall portion
141b are gradually reduced in diameter from the joint portion 142 and connected to
the inclined portion 141c. The inclined portion 141c is inclined radially inward from
the connection wall portion 141b toward the support portion 145. The planetary reduction
gear 4 and the differential mechanism 5, which are the power transmission mechanism
3, are accommodated inside the peripheral wall portion 141.
[0080] The gear case 14 is positioned closer to the differential mechanism 5 (left side
in the drawing) when viewed from the motor case 10. The joint portion 142 of the gear
case 14 is joined to the joint portion 123 of the second case member 12 of the motor
case 10 from the rotation axis X direction. The gear case 14 and the second case member
12 are connected to each other with bolts (not illustrated).
[0081] A space formed inside the joined motor case 10 and gear case 14 is divided into two
spaces by the wall portion 120 (cover) of the second case member 12. A side of the
wall portion 120 in the motor case 10 is a motor chamber Sa that accommodates the
motor 2, and a side of the the wall portion 120 in the gear case 14 is a gear chamber
Sb that accommodates the power transmission mechanism 3. The wall portion 120 as the
cover is sandwiched between the motor 2 and the differential mechanism 5 inside the
housing HS.
[0082] The cover may have a portion accommodated in the housing HS, or the entire cover
may be accommodated in the housing HS like the wall portion 120. The cover may be,
for example, separate from the second case member 12. In this case, the cover may
be sandwiched and fixed between the motor case 10 and the gear case 14. A part of
the cover may be exposed outside of the housing HS.
[0083] The motor 2 includes the cylindrical motor shaft 20, the cylindrical rotor core 21
fitted onto the motor shaft 20, and a stator core 25 surrounding an outer periphery
of the rotor core 21 with a gap therebetween.
[0084] In the motor shaft 20, the bearings B1 and B1 are fitted and fixed to both sides
of the rotor core 21.
[0085] The bearing B1 positioned on the one end 20a (right side in the drawing) of the motor
shaft 20 when viewed from the rotor core 21 is supported on the inner periphery of
the motor support portion 135 of the cover member 13. The bearing B1 positioned on
the other end 20b side (left side in the drawing) is supported on the inner periphery
of the cylindrical motor support portion 125 of the second case member 12.
[0086] The motor support portions 135 and 125 are respectively disposed facing the one end
portion 21a and the other end portion 21b of the rotor core 21, with a gap therebetween
in the rotation axis X direction, on an inner diameter side of coil ends 253a and
253b, which will be described later.
[0087] The rotor core 21 is formed by laminating a plurality of silicon steel plates. Each
of the silicon steel plates is fitted onto the motor shaft 20 such that relative rotation
with respect to the motor shaft 20 is restricted.
[0088] When viewed from the rotation axis X direction of the motor shaft 20, the silicon
steel plate has a ring shape. On an outer peripheral side of the silicon steel plate,
N-pole and S-pole magnets (not illustrated) are alternately provided in a circumferential
direction around the rotation axis X.
[0089] The stator core 25 surrounding the outer periphery of the rotor core 21 is formed
by laminating a plurality of electromagnetic steel plates. The stator core 25 is fixed
to an inner periphery of the cylindrical support wall portion 111 of the first case
member 11.
[0090] Each of the electromagnetic steel plates includes a ring-shaped yoke portion 251
fixed to the inner periphery of the support wall portion 111, and a teeth portion
252 protruding from an inner periphery of the yoke portion 251 toward the rotor core
21.
[0091] In the present embodiment, the stator core 25 in which a winding 253 is wound around
a plurality of teeth portions 252 in a distributed manner is adopted. The stator core
25 is longer than the rotor core 21 in the rotation axis X direction by lengths of
the coil ends 253a and 253b protruding in the rotation axis X direction.
[0092] A stator core in which windings are concentratedly wound around each of the plurality
of teeth portions 252 protruding toward the rotor core 21 may be adopted.
[0093] The opening 120a is provided in the wall portion 120 (motor support portion 125)
of the second case member 12. The other end 20b side of the motor shaft 20 penetrates
through the opening 120a to the differential mechanism 5 (left side in the drawing)
and is positioned in the gear case 14.
[0094] The other end 20b of the motor shaft 20 faces a side gear 54A, which will be described
later, inside the gear case 14 with a gap therebetween in the rotation axis X direction.
[0095] A lip seal RS is inserted between the motor shaft 20 and the opening 120a of the
wall portion 120.
[0096] The oil OL for lubricating the planetary reduction gear 4 and the differential mechanism
5 is sealed in an inner diameter side of the gear case 14.
[0097] The lip seal RS is provided to prevent the oil OL in the gear case 14 from flowing
into the motor case 10.
[0098] As illustrated in FIG. 4, a sun gear 41 of the planetary reduction gear 4 is spline-fitted
in a region of the motor shaft 20 positioned in the gear case 14.
[0099] A tooth portion 41a is formed on an outer periphery of the sun gear 41, and a large-diameter
gear portion 431 of a stepped pinion gear 43 meshes with the tooth portion 41a.
[0100] The stepped pinion gear 43 includes the large-diameter gear portion 431 (large pinion)
that meshes with the sun gear 41 and a small-diameter gear portion 432 (small pinion)
that has a smaller diameter than the large-diameter gear portion 431.
[0101] The large-diameter gear portion 431 and the small-diameter gear portion 432 are integrated
gear components disposed side by side in a direction of an axis X1 parallel to the
rotation axis X.
[0102] An outer periphery of the small-diameter gear portion 432 meshes with an inner periphery
of a ring gear 42. The ring gear 42 has a ring shape surrounding the rotation axis
X with a gap therebetween. On an outer periphery of the ring gear 42, engagement teeth
are provided, and the engagement teeth are spline-fitted to a teeth portion 146a provided
on an inner periphery of the connection wall portion 141b. Rotation of the ring gear
42 around the rotation axis X is restricted.
[0103] A pinion shaft 44 penetrates inner diameter sides of the large-diameter gear portion
431 and the small-diameter gear portion 432. The stepped pinion gear 43 is rotatably
supported on an outer periphery of the pinion shaft 44 via needle bearings NB and
NB.
[0104] As illustrated in FIG. 3, the differential mechanism 5 includes the differential
case 50 as an input element, the drive shafts DA and DB (output shafts) as output
elements, and a differential gear set as a differential element. Although detailed
description is omitted, the differential case 50 may be configured by two case members
assembled in a rotation axis direction.
[0105] The differential case 50 also functions as a carrier that supports the stepped pinion
gear 43 of the planetary reduction gear 4. The stepped pinion gear 43 is rotatably
supported by the differential case 50 via the pinion shaft 44. As illustrated in FIG.
7, three stepped pinion gears 43 are disposed at intervals in the circumferential
direction around the rotation axis X.
[0106] As illustrated in FIG. 3, in the differential case 50, as the differential gear set,
a pinion mate gear 52, which is a bevel gear type differential gear, and side gears
54A and 54B are provided. The pinion mate gear 52 is supported by a pinion mate shaft
51.
[0107] The pinion mate shaft 51 includes a central member 510 disposed on the rotation axis
X and a shaft member 511 connected to an outer diameter side of the central member
510. Although not illustrated, a plurality of shaft members 511 are provided at equal
intervals in the circumferential direction around the rotation axis X. The shaft member
511 is inserted through a support hole 69 of the differential case 50 extending in
the radial direction and supported.
[0108] The pinion mate gear 52 is fitted onto each of the shaft members 511 one by one and
is rotatably supported.
[0109] In the differential case 50, the side gear 54A is positioned on one side of the central
member 510 in the rotation axis X direction, and the side gear 54B is positioned on
the other side of the central member 510. The side gears 54A and 54B are rotatably
supported by the differential case 50.
[0110] The side gear 54A meshes with the pinion mate gear 52 from one side in the rotation
axis X direction. The side gear 54B meshes with the pinion mate gear 52 from the other
side in the rotation axis X direction.
[0111] An opening 60 and the tubular wall portion 61 surrounding the opening 60 and extending
toward the motor case 10 are provided in a central portion of one end side (right
side in the drawing) of the differential case 50. An outer periphery of the tubular
wall portion 61 is supported by the wall portion 120 of the second case member 12
via the bearing B2.
[0112] The drive shaft DA inserted through the opening 60 is inserted into the differential
case 50 from the rotation axis X direction. The drive shaft DA penetrates the insertion
hole 130a of the wall portion 130 of the cover member 13, and is provided across inner
diameter sides of the motor shaft 20 of the motor 2 and the sun gear 41 of the planetary
reduction gear 4 in the rotation axis X direction.
[0113] As illustrated in FIG. 3, a through hole 65 and a tubular wall portion 66 surrounding
the through hole 65 are formed in a central portion of the other end side (left side
in the drawing) of the differential case 50. A bearing B2 is fitted onto the tubular
wall portion 66. The bearing B2 fitted onto the tubular wall portion 66 is held by
the support portion 145 of the gear case 14. The tubular wall portion 66 of the differential
case 50 is rotatably supported by the gear case 14 via the bearing B2.
[0114] The drive shaft DB penetrating an opening 145a of the gear case 14 is inserted into
the support portion 145 from the rotation axis X direction. The drive shaft DB is
rotatably supported by the support portion 145. The tubular wall portion 66 functions
as a shaft support portion that supports an outer periphery of the drive shaft DB.
[0115] A lip seal RS is fixed to an inner periphery of the opening 145a. A lip portion (not
illustrated) of the lip seal RS comes into elastic contact with an outer periphery
of the tubular wall portion 540 of the side gear 54B that is fitted onto the drive
shaft DB.
[0116] As a result, a gap between the outer periphery of the tubular wall portion 540 of
the side gear 54B and the inner periphery of the opening 145a is sealed.
[0117] Inside the differential case 50, distal end portions of the drive shafts DA and DB
face each other with a gap therebetween in the rotation axis X direction.
[0118] The side gears 54A and 54B supported by the differential case 50 are spline-fitted
to outer peripheries of the distal end portions of the drive shafts DA and DB. The
side gears 54A and 54B and the drive shafts DA and DB are connected to each other
so as to be integrally rotatable around the rotation axis X.
[0119] In this state, the side gears 54A and 54B are disposed facing each other with a gap
therebetween in the rotation axis X direction. The central member 510 of the pinion
mate shaft 51 is positioned between the side gears 54A and 54B.
[0120] The pinion mate gear 52 is assembled to the side gear 54A positioned on one side
in the rotation axis X direction and the side gear 54B positioned on the other side
in a state in which teeth portions thereof are meshed with each other.
[0121] As illustrated in FIG. 4, a support hole 62 at one end 44a of the pinion shaft 44
is formed on an outer diameter side of the opening 60 on the one end side (right side
in the drawing) of the differential case 50. A support hole 68 at the other end 44b
of the pinion shaft 44 is formed on the other end side (left side in the drawing)
of the differential case 50.
[0122] The support holes 62 and 68 are formed at overlapping positions in the rotation axis
X direction. The support holes 62 and 68 are formed at intervals in the circumferential
direction around the rotation axis X according to a position where the stepped pinion
gear 43 is disposed. The one end 44a of the pinion shaft 44 is inserted into the support
hole 62, and the other end 44b is inserted into the support hole 68. The other end
44b of the pinion shaft 44 is press-fitted into the support hole 68, so that the pinion
shaft 44 is fixed to the differential case 50 so as not to be rotatable relative to
the differential case 50. The stepped pinion gear 43 fitted onto the pinion shaft
44 is rotatably supported around the axis X1 parallel to the rotation axis X.
[0123] Although not illustrated, the oil OL for lubrication is stored inside the gear case
14. When the differential case 50 rotates around the rotation axis X, the oil OL is
scraped up by the differential case 50.
[0124] Although detailed description is omitted, an oil passage, an oil hole, and the like
for introducing the oil OL scraped up by the differential case 50 are provided in
the differential case 50, the pinion shaft 44, and the like. As a result, the oil
OL is easily introduced into rotating members such as the bearing B2 and the needle
bearing NB.
[0125] As illustrated in FIG. 7, a catch tank 15 is provided above the differential case
50 inside the gear case 14. The catch tank 15 is positioned on one side (left side
in the drawing) of a vertical line VL orthogonal to the rotation axis X. The catch
tank 15 and an accommodation portion 140 of the differential case 50 communicate with
each other via a communication port 147. A part of the oil OL scraped up by the differential
case 50 and scattered flows into the catch tank 15 from the communication port 147
and is collected.
[0126] When the vehicle equipped with the unit 1 travels forward, the differential case
50 rotates in a counterclockwise direction CCW around the rotation axis X when viewed
from the motor case 10. As illustrated in FIG. 4, the small-diameter gear portion
432 of the stepped pinion gear 43 meshes with the ring gear 42 fixed to an inner periphery
of the gear case 14. Therefore, as illustrated in FIG. 7, the large-diameter gear
portion 431 of the stepped pinion gear 43 revolves around the rotation axis X in the
counterclockwise direction CCW while rotating around the axis X1 in a clockwise direction.
[0127] The catch tank 15 is positioned on a left side of the vertical line VL, that is,
on a downstream side in a rotation direction of the differential case 50. As a result,
most of the oil OL scraped up by the differential case 50 rotating around the rotation
axis X can flow into the catch tank 15.
[0128] As illustrated in FIG. 3, the catch tank 15 is connected to a space Rx between the
lip seal RS and the bearing B2 via an oil passage 151a. The catch tank 15 is connected
to an oil cooler 83 (see FIG. 6) via an oil passage, a pipe, or the like (not illustrated).
The oil cooler 83 is connected to the oil hole 136a (see FIG. 3) formed in the connection
wall 136 via a pipe, an oil passage, or the like (not illustrated).
[0129] An oil hole Ha is formed in the peripheral wall portion 141 of the gear case 14.
The oil hole Ha is connected to the oil hole 136b formed in the internal space Sc
via a pipe (not illustrated). The oil OL discharged from the internal space Sc through
the oil hole 136b is supplied again into the gear chamber Sb through the oil hole
Ha.
[0130] As illustrated in FIG. 6, the unit 1 is provided with a circulation system 80 for
the cooling water CL. The circulation system 80 circulates the cooling water CL between
the cooling path CP 1 of the motor case 10 and the cooling path CP2 of the inverter
case 17. The circulation system 80 further includes the oil cooler 83, a water pump
WP, and a radiator 82 between the cooling path CP1 and the cooling path CP2, which
are connected by pipes or the like through which the cooling water CL flows.
[0131] The water pump WP pumps the cooling water CL in the circulation system 80.
[0132] The radiator 82 is a device that dissipates heat of the cooling water CL to cool
the cooling water CL.
[0133] The oil cooler 83 is a heat exchanger that exchanges heat between the cooling water
CL and the oil OL. The oil OL collected by the catch tank 15 provided in the gear
chamber Sb of the gear case 14 is introduced into the oil cooler 83. The oil OL is
cooled by heat exchange with the cooling water CL. The cooled oil OL is supplied from
the oil hole 136a of the motor case 10 to the internal space Sc. The oil OL supplied
to the oil cooler 83 is not limited to the oil OL collected by the catch tank 15,
and may be supplied from another oil passage appropriately provided in the housing
HS. The oil OL discharged from the oil cooler 83 may be supplied to a location other
than the internal space Sc.
[0134] The cooling water CL is supplied to the oil cooler 83 after flowing through the cooling
path CP2 in the inverter case 17 and the cooling path CP1 in the motor case 10. After
the heat exchange with the oil OL in the oil cooler 83, the cooling water CL is cooled
by the radiator 82 and supplied to the cooling path CP2 of the inverter case 17 again.
[0135] Functions of the unit 1 having such a configuration will be described.
[0136] As illustrated in FIG. 1, in the unit 1, the planetary reduction gear 4, the differential
mechanism 5, and the drive shafts DA and DB are provided along the transmission path
of the output rotation of the motor 2.
[0137] As illustrated in FIG. 3, when the motor 2 is driven and the rotor core 21 rotates
around the rotation axis X, the rotation is input to the sun gear 41 of the planetary
reduction gear 4 via the motor shaft 20 that rotates integrally with the rotor core
21.
[0138] In the planetary reduction gear 4, the sun gear 41 serves as an input portion for
the output rotation of the motor 2, and the differential case 50 supporting the stepped
pinion gear 43 serves as an output portion for the input rotation.
[0139] As illustrated in FIG. 4, when the sun gear 41 rotates around the rotation axis X
by the input rotation, the stepped pinion gear 43 (large-diameter gear portion 431
and small-diameter gear portion 432) rotates around the axis X1 by the rotation input
from the sun gear 41.
[0140] Here, the small-diameter gear portion 432 of the stepped pinion gear 43 meshes with
the ring gear 42 fixed to the inner periphery of the gear case 14. Therefore, the
stepped pinion gear 43 revolves around the rotation axis X while rotating around the
axis X1.
[0141] Here, in the stepped pinion gear 43, an outer diameter of the small-diameter gear
portion 432 is smaller than an outer diameter of the large-diameter gear portion 431.
[0142] As a result, the differential case 50 supporting the stepped pinion gear 43 rotates
around the rotation axis X at a rotation speed lower than that of the rotation input
from the motor 2.
[0143] Therefore, the rotation input to the sun gear 41 of the planetary reduction gear
4 is greatly decelerated by the stepped pinion gear 43 and then output to the differential
case 50 (differential mechanism 5).
[0144] As illustrated in FIG. 3, when the differential case 50 rotates around the rotation
axis X by the input rotation, the drive shafts DA and DB meshing with the pinion mate
gear 52 rotate around the rotation axis X in the differential case 50. As a result,
the left and right drive wheels K and K (see FIG. 1) of the vehicle equipped with
the unit 1 are rotated by the transmitted rotational driving force.
[0145] As illustrated in FIG. 3, the oil OL for lubrication and cooling is stored in the
gear chamber Sb. In the gear chamber Sb, when the output rotation of the motor 2 is
transmitted, the stored oil OL is scraped up by the differential case 50 rotating
around the rotation axis X.
[0146] As illustrated in FIG. 3 and FIG. 4, the scraped up oil OL lubricates a meshing portion
between the sun gear 41 and the large-diameter gear portion 431, a meshing portion
between the small-diameter gear portion 432 and the ring gear 42, and meshing portions
between the pinion mate gear 52 and the side gears 54A and 54B. The heat exchange
with the oil OL cools these meshing portions.
[0147] As illustrated in FIG. 7, the differential case 50 rotates around the rotation axis
X in the counterclockwise direction CCW.
[0148] The catch tank 15 is provided on an upper portion of the gear case 14. The catch
tank 15 is positioned on the downstream side in the rotation direction of the differential
case 50, and a part of the oil OL scraped up by the differential case 50 flows into
the catch tank 15.
[0149] As illustrated in FIG. 3, a part of the oil OL flowing into the catch tank 15 is
supplied to the space Rx between the lip seal RS and the bearing B2 via the oil passage
151a to lubricate the bearing B2. A part of the oil OL flowing into the catch tank
15 is introduced into an oil cooler 83 (see FIG. 6) via a pipe (not illustrated) and
cooled. The cooled oil OL is supplied to the internal space Sc (see FIG. 3) formed
in the connection wall 136 through the oil hole 136a. The oil OL supplied to the internal
space Sc lubricates the bearing B4 and is discharged from the oil hole 136b. The oil
OL discharged from the oil hole 136b is supplied into the gear chamber Sb from the
oil hole Ha via a pipe or the like (not illustrated).
[0150] FIG. 8 is a diagram illustrating a covering 90 for covering the housing HS and a
box 93 for introducing a liquid Lq.
[0151] FIG. 9 is a view of FIG. 8 when viewed from the rotation axis X direction. In FIG.
8 and FIG. 9, the covering 90 is indicated by a broken line for easy understanding.
[0152] As illustrated in FIG. 8, as a noise countermeasure the housing HS can be covered
with the covering 90 which is a separate component. The noise countermeasure means,
for example, a countermeasure for reducing noise that is generated in various components
(for example, power transmission mechanism 3 and motor 2) of the unit 1 and leaks
to the outside. The noise is sound or electromagnetic noise.
[0153] The covering 90 may have a rectangular parallelepiped shape that accommodates the
entire housing HS as in the illustrated example, but is not limited thereto. The covering
90 is made of, for example, a flexible material and can be wound around a surface
of the housing HS without a gap. Further, the covering 90 may cover only the gear
case 14 of the housing HS. Alternatively, the gear case 14 and the motor case 10 may
be covered with the covering 90, and the inverter case 17 may be exposed from the
covering 90.
[0154] The covering 90 can be made of a material having a noise reduction function (for
example, soundproof function, sound absorption function, and sound insulation function).
The material applicable to the covering 90 includes, for example, organic materials,
and metal materials. A material containing an organic material is preferable to enhance
a sound reduction effect. A material containing a metal material is preferable to
enhance an effect of reducing the electromagnetic noise.
[0155] Among the organic materials, for example, urethane, rubber, and polyethylene have
a good sound reduction effect and are particularly preferred materials.
[0156] Among the metal materials, particularly preferred materials are materials having
higher specific conductivity/specific permeability and/or materials having higher
specific conductivity × specific permeability than materials constituting the housing
HS because the effect of reducing the electromagnetic noise is further enhanced. For
example, when the material of the housing HS member is a material containing aluminum
as a main component, the metal material applied to the covering 90 is preferably a
material containing gold, silver, and copper.
[0157] The covering 90 may be formed by laminating different materials and/or mixing different
materials. For example, when the covering 90 is formed by laminating a metal material
and an organic material, or when the covering 90 is made of a material in which particles
(metal particles, alloy particles, or the like) containing a metal are mixed with
an organic material, the covering 90 is preferable as a countermeasure against sound
and electromagnetic noise.
[0158] In order to enhance the sound reduction effect, the covering 90 may have a porous
structure.
[0159] In covering the housing HS with the covering 90, a material having a waterproof effect
can be used to improve durability. The metal material has a waterproof effect. Examples
of organic materials having a waterproof effect include rubber and polyethylene.
[0160] As illustrated in FIG. 8, as an electrical component, a drive battery 91 of the motor
2 is attached to an outside of the covering 90. The drive battery 91 is connected
to the inverter 7 via wiring (not illustrated). The drive battery 91 is fixed to an
upper portion of the housing HS from the outside of the covering 90. When viewed in
the radial direction of the rotation axis X, a part of the drive battery 91 is set
off from the covering 90.
[0161] The electrical component is not limited to the drive battery 91, and may be, for
example, a connector or a park actuator. When the inverter case 17 is not covered
with the covering 90, the inverter 7 may be used as the electrical component.
[0162] As illustrated in FIG. 9, the vehicle is provided with a ventilation port VP that
communicates a space SP below the vehicle in which the unit 1 is disposed with an
inside of a vehicle room VR in which an occupant gets on.
[0163] FIG. 10 is a diagram illustrating a vehicle VH equipped with the unit 1 and a fuel
cell 95.
[0164] As illustrated in FIG. 10, the unit 1 is disposed rear of vehicle VH, and the fuel
cell 95 is disposed in front of the vehicle VH. A hydrogen tank 96 is disposed below
the vehicle room VR at a center of the vehicle VH. The hydrogen tank 96 is connected
to the fuel cell 95 via a pipe 99.
[0165] A water storage tank 97 is disposed rear of the unit 1 in the vehicle VH. A drainage
port 97a is provided in a lower portion of the water storage tank 97.
[0166] The fuel cell 95 and the unit 1 are connected via a drainage pipe 98A. The unit 1
and the water storage tank 97 are connected via a drainage pipe 98B. That is, the
fuel cell 95 and the water storage tank 97 are connected via the drainage pipe 98A,
the unit 1, and the drainage pipe 98B.
[0167] The fuel cell 95 is also electrically connected to the unit 1 via wiring (not illustrated).
[0168] In the vehicle VH, power is supplied from the drive battery 91 (see FIG. 8) to the
motor 2. When the drive battery 91 is charged, or when power supplied from the drive
battery 91 to the motor 2 is insufficient, power is supplied from the fuel cell 95.
[0169] As illustrated in FIG. 10, hydrogen gas is supplied from the hydrogen tank 96 to
an anode of the fuel cell 95, and oxygen gas (air) taken in from outside air is supplied
to a cathode of the fuel cell 95, and an electrochemical reaction is caused to generate
electricity. As a result of the electrochemical reaction between the hydrogen gas
and the oxygen gas, the liquid Lq (water: H
2O) is generated.
[0170] The generated liquid Lq is introduced into the water storage tank 97 at the rear
of the vehicle VH via the drainage pipes 98A and 98B, and is discharged to an outside
of the vehicle from the drainage port 97a of the water storage tank 97. Exhaust gas
(mainly nitrogen gas) generated by the electrochemical reaction may be introduced
into the drainage pipes 98A and 98B.
[0171] As described above, the drainage pipes 98A and 98B are each connected to the unit
1. That is, the liquid Lq is introduced into the water storage tank 97 via the unit
1. In the embodiment, the liquid Lq is used as a countermeasure against heat for the
unit 1.
[0172] As illustrated in FIG. 8, in the unit 1, heat is likely to be generated in the housing
HS due to rotation of components constituting the motor 2 and the power transmission
mechanism 3. As illustrated in FIG. 8, since the housing HS is covered with the covering
90, the generated heat is likely to be accumulated. In the embodiment, a temperature
rise of the housing HS is reduced by exchanging heat between the housing HS and the
liquid Lq which is a coolant (refrigerant).
[0173] For heat exchange, for example, the liquid Lq is interposed between an outer surface
of the covering 90 and an outer surface of the housing HS. As a method of interposing
the liquid Lq between the outer surface of the covering 90 and the outer surface of
the housing HS, for example, a retention portion for retaining the liquid Lq can be
provided between the outer surface of the covering 90 and the outer surface of the
housing HS. Further, a flow path through which the liquid Lq flows can be provided
between the outer surface of the covering 90 and the outer surface of the housing
HS.
[0174] Here, "between the outer surface of the covering 90 and the outer surface of the
housing HS" includes a concept of "between the outer surface of the covering 90 and
an inner surface of the covering 90", and includes, for example, a configuration in
which a retention portion or a flow path is formed in the covering 90.
[0175] Further, "between the outer surface of the covering 90 and the outer surface of the
housing HS" includes a concept of "between the inner surface of the covering 90 and
the outer surface of the housing HS". This concept includes, for example, a configuration
in which a clearance between the covering 90 and the housing HS is a retention portion
or a flow path. This concept also includes a configuration in which a retention portion
(such as the box 93 into which the liquid Lq is introduced) or a flow path (such as
a pipe through which the liquid Lq flows) is provided between the covering 90 and
the housing HS, or the like.
[0176] As illustrated in FIG. 8, in the embodiment, the box 93 is provided between the inner
surface of the covering 90 and the outer surface of the housing HS as a retention
portion into which liquid Lq is introduced. In FIG. 8 and FIG. 9, the box 93 is illustrated
with hatching for easy understanding.
[0177] As illustrated in FIG. 8, the box 93 is installed in a lower portion of the housing
HS in the covering 90. When viewed in the radial direction of the rotation axis X,
the box 93 has a portion that overlaps the gear case 14 in which the power transmission
mechanism 3 is accommodated and the motor case 10 in which the motor 2 is accommodated.
[0178] An introduction port 93a for the liquid Lq is provided at one end (right side in
the drawing) of the box 93 in the rotation axis X direction, and a discharge port
93b is provided at the other end (left side in the drawing) of the box 93. The drainage
pipe 98A extending from the fuel cell 95 penetrates the covering 90 and is connected
to the introduction port 93a of the box 93. The drainage pipe 98B extending from the
water storage tank 97 penetrates the covering 90 and is connected to the discharge
port 93b of the box 93. The introduction port 93a and the discharge port 93b are provided
apart from a bottom surface 93d of the box 93.
[0179] The liquid Lq flowing through the drainage pipe 98A is introduced into the box 93
through the introduction port 93a. When the liquid Lq retaining in the box 93 reaches
a height of the discharge port 93b, the liquid Lq is discharged to the drainage pipe
98B through the discharge port 93b.
[0180] The heat exchange between the liquid Lq retaining in the box 93 and the housing HS
reduces the temperature rise of the housing HS. Since the covering 90 includes the
box 93, the covering 90 functions as a heat exchange unit with the housing HS.
[0181] The liquid Lq retaining in the box 93 has a portion that overlaps the power transmission
mechanism 3 when viewed in the radial direction of the rotation axis X. As illustrated
in FIG. 8, the oil OL is stored in a lower portion of a gear chamber Sb formed in
the gear case 14 of the housing HS. A temperature of the oil OL stored in the gear
chamber Sb is likely to rise due to heat exchange with the meshing portions of the
respective gears constituting the power transmission mechanism 3. Since the box 93
is positioned below the gear chamber Sb in a gravity direction, heat is easily exchanged
with the oil OL stored in the gear chamber Sb. This reduces a temperature rise of
the oil OL stored in the gear chamber Sb, thereby contributing to a countermeasure
against heat for the housing HS.
[0182] The liquid Lq retaining in the box 93 has a portion that overlaps the motor 2 when
viewed in the radial direction of the rotation axis X. FIG. 8 illustrates an example
in which the oil OL is stored in the gear chamber Sb. When the motor 2 is directly
cooled by the oil OL, the oil OL can also be stored in the motor chamber Sa that accommodates
the motor 2. In this case, the temperature rise of the oil OL scraped up by the motor
2 can be reduced by heat exchange with the liquid Lq accumulated in the box.
[0183] Further, since the liquid Lq is interposed between the outer surface of the covering
90 and the outer surface of the housing HS, external leakage of noise generated from
the power transmission device and the motor 2 is reduced.
[0184] FIG. 11 is a view illustrating a state in which the box 93 is viewed from above together
with the housing HS. FIG. 12 is a view illustrating a cross section of the box 93
taken along line A-A in FIG. 11 together with the housing HS. In FIG. 11, an upper
outer surface 93c of the box 93 is illustrated with hatching to facilitate understanding
of an area of the box 93.
[0185] As illustrated in FIG. 11, the box 93 has a substantially rectangular shape when
viewed from above. The box 93 is formed in such a size that the housing HS is disposed
inside an outer peripheral edge 930 of the box 93.
[0186] As illustrated in FIG. 12, the box 93 has a rectangular parallelepiped shape having
a thickness in a vertical line direction. As illustrated in FIG. 12, a recess 931
is provided in the upper outer surface 93c of the box 93. The recess 931 opens upward
in the vertical line direction. An inner periphery of the recess 931 is formed according
to a shape of a lower outer surface HSS of the housing HS. The lower outer surface
HSS of the housing HS is disposed in the recess 931. In the recess 931, the upper
outer surface 93c and the lower outer surface HSS are in contact with each other.
Accordingly, heat exchange efficiency between the liquid Lq in the box 93 and the
housing HS can be improved.
[0187] The illustrated box 93 is merely an example. The box 93 may have a rectangular parallelepiped
shape in which the recess 931 is not formed, or may have a tubular shape. Further,
a plurality of boxes 93 may be provided so as to surround the housing HS.
[0188] When the liquid Lq in the box 93 reaches the height of the discharge port 93b, the
liquid Lq is discharged from the discharge port 93b, and a new liquid Lq is introduced
from the introduction port 93a. As described above, since the liquid Lq in the box
93 is normally replaced, heat exchange with the housing HS can be efficiently performed.
[0189] As illustrated in FIG. 10, the unit 1 and the water storage tank 97 are positioned
on a rear side of the vehicle VH with respect to the fuel cell 95 in which the liquid
Lq is generated. That is, the housing HS of the unit 1 and the drainage port 97a of
the water storage tank 97 are disposed close to each other. Accordingly, the drainage
pipe 98B that connects the housing HS of the unit 1 and the drainage port 97a of the
water storage tank 97 can be shortened. This is advantageous in cost, weight, and
the like.
[0190] When the liquid Lq is discharged from the discharge port 93b of the box 93 of the
housing HS and the drainage port 97a of the water storage tank 97, a drainage sound
may be generated. As illustrated in FIG. 10, the housing HS of the unit 1 and the
water storage tank 97 are disposed rear of the vehicle room VR in the vehicle VH.
Accordingly, the sound generated from the housing HS and the drainage sound of the
liquid Lq hardly reach the vehicle room VR, which is advantageous for noise countermeasures.
[0191] The drainage port 97a of the water storage tank 97 is disposed rear of the housing
HS in the vehicle VH. For example, when viewed in the gravity direction, the housing
HS has a portion positioned between the drainage port 97a of the water storage tank
97 and the vehicle room VR. With such a configuration, the housing HS functions as
a wall that cuts off discharge noise, which is noise generated from the water storage
tank 97, and thus is advantageous for noise countermeasures.
[0192] The temperature rise of the unit 1 disposed below the vehicle VH is reduced by performing
heat exchange with traveling wind of the vehicle VH, but when the unit 1 is disposed
on the rear side of the vehicle VH, the unit 1 is less likely to be affected by the
traveling wind of the vehicle. As illustrated in FIG. 9, in the embodiment, the ventilation
port VP that communicates the inside of the vehicle room VR with the space SP in which
the housing HS is disposed is provided.
[0193] By driving an air conditioner in the vehicle room VR or opening windows of the vehicle
room VR, the air Air in the vehicle room VR is discharged from the ventilation port
VP and flows into the space SP. A temperature of the air Air in the vehicle room VR
is adjusted according to an outside air temperature. For example, when the outside
air temperature is high, cooling is used in the vehicle VH, or the windows are opened.
Further, for example, when the outside air temperature is low, heating is used.
[0194] By flowing the air Air whose temperature is adjusted according to the outside air
temperature into the space SP and exchanging heat with the housing HS, heat exchange
can be performed in a direction that brings the temperature of the housing HS closer
to an appropriate temperature even on the rear side of the vehicle, which is less
likely to be affected by the traveling wind. A fan or the like may be provided so
that the air Air in the vehicle room VR can easily flow into the space SP.
[0195] As described above, the vehicle VH according to the embodiment has the following
configurations.
- (1) The vehicle VH includes: a housing HS that accommodates the power transmission
mechanism 3;
the covering 90 having a portion that covers the housing HS; and
the liquid Lq interposed between the outer surface of the covering 90 and the outer
surface of the housing HS.
[0196] With this configuration, the liquid Lq can be effectively used. Noise is generated
by an operation of the power transmission mechanism 3 accommodated in the housing
HS. By covering the housing HS that accommodates the power transmission mechanism
3 with the covering 90, a countermeasure against noise can be taken. However, since
the housing HS is covered with the covering 90, heat is likely to be accumulated.
By interposing the liquid Lq between the outer surface of the covering 90 and the
outer surface of the housing HS, the housing HS can be cooled by the liquid Lq. Further,
the liquid Lq also contributes to a countermeasure against noise leaking to an outside
of the housing HS. In this way, the liquid Lq can be effectively used as a countermeasure
against heat or noise in the vehicle VH.
[0197] (2) The liquid Lq is drainage of the fuel cell 95.
[0198] The liquid Lq (water) is generated by power generation in the fuel cell 95. By interposing
the liquid Lq discharged from the water storage tank 97 to the outside of the vehicle
between the outer surface of the covering 90 and the outer surface of the housing
HS, the drainage of the fuel cell 95 can be effectively used.
[0199] (3) The vehicle VH includes: the housing HS that accommodates the power transmission
mechanism 3; and
the covering 90 (heat exchange unit) that performs heat exchange between the housing
HS and the liquid Lq that is drainage of the fuel cell 95.
[0200] The liquid Lq discharged from the water storage tank 97 to the outside of the vehicle
is introduced into the box 93 of the covering 90, and heat exchange with the housing
HS is performed, and thus the drainage of the fuel cell 95 can be effectively used.
[0201] (4, 5) The vehicle VH includes: the drive battery 91 (electrical component) fixed
to the outer surface of the housing HS.
[0202] When viewed in the radial direction of the rotation axis X, the drive battery 91
has a portion offset from the covering 90.
[0203] The electrical component (for example, park actuator or connector) is exposed to
an outside of the covering 90 and fixed to the housing HS covered with the covering
90.
[0204] Accordingly, as in the example in FIG. 8, when the liquid Lq is interposed between
the inner surface of the covering 90 and the outer surface of the housing HS, a contact
area between the electrical component and the liquid Lq introduced into the covering
90 can be reduced. Accordingly, interference of the liquid Lq with the electrical
component can be reduced.
[0205] When the liquid Lq is interposed between the inner surface of the covering 90 and
the outer surface of the covering 90, the outer surfaces of the covering 90 and the
housing HS can be brought close to each other. Accordingly, the heat exchange efficiency
between the liquid Lq and the housing HS can be improved, which contributes to a countermeasure
against heat for the housing HS. Further, when the electrical component is also covered
with the covering 90, a gap generated by the covering 90 being separated from the
surface of the housing HS is reduced, and thus a noise countermeasure effect can be
improved.
[0206] (6) The housing HS is positioned on the vehicle VH rear side of the vehicle room
VR.
[0207] The vehicle VH includes the ventilation port VP that communicates with the space
SP in which the housing HS is disposed, in the vehicle room VR.
[0208] By providing the ventilation port VP that communicates the inside of the vehicle
room VR with the space SP in which the housing HS is disposed, the air Air in the
vehicle room VR can be sent to the space SP. Accordingly, since the air Air in the
vehicle room VR whose temperature is adjusted according to the outside air temperature
is introduced into the space SP, heat exchange can be performed in a direction approaching
an appropriate temperature of the housing HS even on the rear side of the vehicle
VH, which is less likely to be affected by the traveling wind.
(Modification 1)
[0209] FIG. 13 is a schematic diagram illustrating a covering 90A according to Modification
1.
[0210] FIG. 14 is a schematic diagram of the covering 90A according to Modification 1 when
viewed from a rotation axis X direction.
[0211] As illustrated in FIG. 13 and FIG. 14, in Modification 1, the covering 90A is provided
with an opening 901 that exposes the outer surface of the housing HS.
[0212] As illustrated in FIG. 13, a nozzle 981 for injecting the liquid Lq is attached to
a tip of the drainage pipe 98A through which the liquid Lq discharged from the fuel
cell 95 flows. The nozzle 981 may inject the liquid Lq as a water flow, or may inject
the liquid Lq as a mist.
[0213] By introducing the exhaust gas (mainly nitrogen gas) generated by the electrochemical
reaction of the fuel cell 95 into the drainage pipe 98A, the liquid Lq can be injected
from the nozzle 981.
[0214] As illustrated in FIG. 14, the nozzle 981 is disposed facing the outer surface of
the housing HS exposed from the opening 901 formed in the covering 90A. The liquid
Lq injected from the nozzle 981 is sprayed onto the outer surface of the housing HS.
When the liquid Lq sprayed onto the outer surface of the housing HS is vaporized,
heat of the outer surface of the housing HS is absorbed, thereby contributing to a
countermeasure against heat for the housing HS.
[0215] A part of the liquid Lq sprayed onto the outer surface of the housing HS does not
vaporize, and falls downward along the outer surface of the housing HS according to
gravity in the gravity direction.
[0216] Also in Modification 1, the box 93 is provided as a retention portion of the liquid
Lq in the lower portion of the housing HS. As illustrated in FIG. 13, in the box 93
in Modification 1, an opening 93e is provided in the upper outer surface 93c instead
of the introduction port 93a (see FIG. 8). The liquid Lq falling downward along the
outer surface of the housing HS falls into the box 93 through the opening 93e and
retains therein. The liquid Lq retaining in the box 93 contributes to a countermeasure
against heat by performing heat exchange with the housing HS as in the embodiment.
[0217] The liquid Lq retaining in the box 93 is introduced from the discharge port 93b into
the drainage pipe 98B as in the embodiment.
[0218] According to the configuration in Modification 1, the opening 901 is provided in
the covering 90A to expose the outer surface of the housing HS. The nozzle 981 is
provided at the tip of the drainage pipe 98A through which the liquid Lq discharged
from the fuel cell 95 flows, and the nozzle 981 is disposed at the opening 901. By
injecting the liquid Lq from the nozzle 981 to the outer surface of the housing HS,
the housing HS can be efficiently cooled by vaporization heat.
[0219] A place where the opening 901 is provided is not limited, and may be, for example,
a place where heat is likely to be generated in the upper portion of the housing HS.
By providing the opening 901 in the upper portion of the housing HS, the upper portion
of the housing HS can be cooled with a lower flow rate of liquid Lq compared to a
case in which the retention portion of the liquid Lq is provided up to the upper portion
of the housing HS.
[0220] For example, when the opening 901 is provided in a region of the covering 90A facing
the motor case 10, the liquid Lq sprayed onto the motor case 10 can contribute to
a countermeasure against heat for the motor 2. Further, for example, when the opening
901 is provided in a region of the covering 90A facing the gear case 14, the liquid
Lq sprayed onto the gear case 14 can contribute to a countermeasure against heat for
the power transmission mechanism 3.
[0221] In particular, in Modification 1, spraying of the liquid Lq from the opening 901
onto the outer surface of the housing HS and the box 93 capable of storing the liquid
Lq falling downward along the outer surface of the housing HS are combined. Accordingly,
the liquid Lq can be effectively used as a countermeasure against heat for the housing
HS.
(Modification 2)
[0222] FIG. 15 is a diagram illustrating a covering 90B according to Modification 2.
[0223] As illustrated in FIG. 15, in Modification 2, a flow path 902 through which the liquid
Lq flows is provided in the covering 90B. The flow path 902 can be provided, for example,
between an outer surface and an inner surface of the covering 90B.
[0224] As an example, the flow path 902 may be configured by a tubular member provided integrally
with the covering 90B. The tubular member preferably has flexibility to such an extent
that a space inside a tube is not completely crushed even when the tubular member
is bent along an outer periphery of the housing HS.
[0225] The flow path 902 is connected to the drainage pipe 98A at one end (right side in
the drawing) in the rotation axis X direction of the covering 90B, and is connected
to the drainage pipe 98B at the other end (left side in the drawing).
[0226] The flow path 902 is formed as one flow path that continues from a connection portion
with the drainage pipe 98A to a connection portion with the drainage pipe 98B.
[0227] In a state in which the covering 90B covers a periphery of the housing HS, the flow
path 902 extends along the circumferential direction around the rotation axis X, and
is provided with a phase shift in the rotation axis X direction. Therefore, the flow
path 902 is arranged in a spiral shape surrounding the rotation axis X.
[0228] As in the embodiment, also in Modification 2, since heat exchange is performed between
the liquid Lq flowing through the flow path 902 and the housing HS, the covering 90
functions as a heat exchange unit and contributes to a countermeasure against heat
for the housing HS.
[0229] Further, as compared with a case in which the retention portion of the liquid Lq
is provided in the entire housing HS, the spiral flow path 902 can surround almost
the entire housing HS, so that a countermeasure against heat can be taken with a small
flow rate of the liquid Lq. This contributes to reducing an amount of liquid Lq required
for the entire vehicle VH.
[0230] In FIG. 15, the covering 90B is illustrated as a rectangular parallelepiped shape,
but is not limited thereto. For example, in order to facilitate heat exchange between
the flow path 902 and the housing HS, the covering 90B may have a shape along the
outer surface of the housing HS. Accordingly, an area in which the covering 90 contacts
the outer surface of the housing HS is increased, and the heat exchange efficiency
can be improved.
(Other Modifications)
[0231] In the embodiment and the modifications described above, the example in which the
retention portion into which the liquid Lq is introduced or the flow path is provided
in the covering 90 has been described, but the present invention is not limited thereto.
A heat exchanger (oil cooler) into which the liquid Lq that is the drainage of the
fuel cell 95 and the oil are introduced can be used as a heat exchange unit.
[0232] The oil OL may be used to lubricate and cool the power transmission mechanism 3 or
the motor 2 in the housing HS. For example, in the oil cooler 83 illustrated in FIG.
6, the liquid Lq which is the drainage of the fuel cell 95 may be introduced instead
of the cooling water. Alternatively, an oil cooler different from the oil cooler 83
may be provided.
[0233] In Modification 2, the example in which the flow path 902 is formed between the outer
surface of the covering 90 and the inner surface of the covering 90 has been described,
but the present invention is not limited thereto. The flow path may be a flow path
formed by using a part of the housing HS. For example, a flow path through which the
liquid Lq flows may be formed between the outer surface and the inner surface of the
housing HS.
[0234] A pipe that contacts an oil reservoir in the housing HS may be provided in the covering
90. For example, a pipe through which the liquid Lq, which is the drainage of the
fuel cell 95, flows may be disposed so as to pass the oil stored in the lower portion
of the gear chamber Sb of the housing HS.
[0235] Further, the inverter 7 may be provided adjacent to the housing HS, and a flow path
through which the liquid Lq flows may be provided between the housing HS and the inverter
7 as a heat exchange unit. This contributes to a countermeasure against heat generated
in the inverter 7.
[0236] The drive battery 91 may be provided adjacent to the housing HS, and a flow path
through which the liquid Lq flows may be provided between the housing HS and the drive
battery 91 as a heat exchange unit. This contributes to a countermeasure against heat
generated in the drive battery 91.
[0237] Further, a flow path or a heat exchanger (oil cooler) may be provided as a heat exchange
unit between the housing HS and the covering 90 or in a dead space in the housing
HS.
[0238] In the embodiment and the modifications, the example in which the heat exchange between
the housing HS and the liquid Lq is performed as a countermeasure against heat for
the housing HS has been described, but the present invention is not limited thereto.
[0239] As a countermeasure against heat, for example, it is conceivable to reduce an amount
of heat exchange between the housing HS and other components.
[0240] As a measure to reduce the amount of heat exchange, for example, the amount of heat
exchange between the housing HS and an element outside the housing HS can be reduced.
Further, for example, the amount of heat exchange between the housing HS and an external
heat source having a higher temperature than the housing HS can be reduced. Further,
for example, it is conceivable to take a measure such as reducing the amount of heat
exchange between the housing HS and an external component required to be lower in
temperature than the unit 1 including the housing HS.
[0241] In an embodiment of the present invention, the housing HS that accommodates at least
the power transmission mechanism 3 is taken as an example. In another aspect of the
present invention, the housing HS that accommodates at least the motor 2 may be used.
In this case, the power transmission mechanism 3 may or may not be accommodated in
the same housing HS.
[0242] In another aspect of the present invention, the housing HS that accommodates at least
the inverter 7 may be used. In this case, the power transmission mechanism 3 may or
may not be accommodated in the same housing HS.
[0243] In another aspect of the present invention, the housing HS that accommodates at least
the battery may be used. The battery may be, for example, the drive battery 91 (see
FIG. 8). In this case, the power transmission mechanism 3 may or may not be accommodated
in the same housing HS.
[0244] In an aspect of the present invention, the power transmission mechanism 3 includes,
for example, a gear mechanism and an annular mechanism.
[0245] The gear mechanism includes, for example, a reduction gear mechanism, an acceleration
gear mechanism, and a differential gear mechanism (differential mechanism).
[0246] The reduction gear mechanism and the acceleration gear mechanism include, for example,
a planetary gear mechanism and a parallel gear mechanism.
[0247] The annular mechanism includes, for example, an endless annular component.
[0248] The endless annular component includes, for example, a chain sprocket, a belt and
a pulley.
[0249] The differential mechanism 5 is, for example, a bevel gear type differential gear
or a planetary gear type differential gear.
[0250] The differential mechanism 5 includes a differential case as an input element, two
output shafts as output elements, and a differential gear set as a differential element.
[0251] In the bevel gear type differential gear, the differential gear set includes bevel
gears.
[0252] In the planetary gear type differential gear, the differential gear set includes
planetary gears.
[0253] The unit 1 includes a gear that rotates integrally with the differential case.
[0254] For example, a final gear (differential ring gear) of the parallel gear mechanism
rotates integrally with the differential case. For example, when a carrier of the
planetary gear mechanism is connected to the differential case, a pinion gear rotates
(revolves) integrally with the differential case.
[0255] For example, a reduction gear mechanism is connected downstream of the motor 2. A
differential gear mechanism is connected downstream of the reduction gear mechanism.
That is, a differential gear mechanism is connected downstream of the motor 2 via
a reduction gear mechanism. An acceleration gear mechanism may be used instead of
the reduction gear mechanism.
[0256] A single-pinion type planetary gear mechanism can use, for example, a sun gear as
an input element, a ring gear as a fixed element, and a carrier as an output element.
[0257] A double-pinion type planetary gear mechanism can include, for example, a sun gear
as an input element, a ring gear as an output element, and a carrier as a fixed element.
[0258] As a pinion gear of the single-pinion type planetary gear mechanism or the double-pinion
type planetary gear mechanism, for example, a stepped pinion gear or a non-stepped
pinion gear can be used.
[0259] The stepped pinion gear includes a large pinion and a small pinion. For example,
it is preferable to mesh the large pinion with the sun gear. For example, it is preferable
to fit the small pinion into the ring gear.
[0260] The non-stepped pinion gear is not a stepped pinion gear.
[0261] In the present embodiment, an example in which the unit 1 is mounted on a vehicle
has been described, but the present invention is not limited thereto, and the unit
1 can be applied to a device other than a vehicle. When a plurality of examples and
modifications are described in the present embodiment, these examples and modifications
may be freely combined.
[0262] The embodiment of the present invention has been described above, and the above embodiment
is merely an application example of the present invention and is not intended to limit
the technical scope of the present invention to the specific configuration of the
above embodiment. The embodiment can be changed as appropriate within the scope of
the technical idea of the invention.
DESCRIPTION OF REFERENCE SIGNS
[0263]
- 1
- unit
- 3
- power transmission mechanism
- 90
- covering (heat exchange unit)
- 91
- drive battery (electrical component)
- 92
- ventilation port
- 93
- box
- 95
- fuel cell
- VH
- vehicle
- VR
- vehicle room
- HS
- housing
- Lq
- liquid